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Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | $ 1,933,563 | $ 1,822,100
Less: current regulatory assets | 630,319 | 538,879
Total non-current regulatory assets | 1,303,244 | 1,283,221
Pension |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 631,307 | 637,656
Deferred fuel and purchased power |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 526,666 | 460,561
Income taxes — allowance for funds used during construction (“AFUDC”) equity |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 188,845 | 179,631
Ocotillo deferral |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 131,013 | 138,143
SCR deferral |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 91,514 | 97,624
Retired power plant costs |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 87,325 | 98,692
Lease incentives |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 39,700 | 0
Deferred property taxes |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 34,630 | 41,057
Deferred compensation |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 34,492 | 33,660
Deferred fuel and purchased power — mark-to-market (Note 7) |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 34,131 | 0
Income taxes — investment tax credit basis adjustment |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 33,684 | 23,977
Palo Verde VIEs (Note 6) |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 20,812 | 20,933
Active Union Medical Trust |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 17,759 | 18,226
Power supply adjustor - interest |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 13,899 | 1,541
Navajo coal reclamation |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 11,628 | 13,862
Four Corners cost deferral |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 9,941 | 15,999
Mead-Phoenix transmission line contributions in aid of construction (“CIAC”) |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 8,799 | 9,048
Loss on reacquired debt |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 8,305 | 9,468
Tax expense adjustor mechanism (b) (e) |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 5,354 | 5,845
Lost fixed cost recovery |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | 0 | 9,547
Other |  |
Detail of regulatory assets |  |
Regulatory asset including deferred fuel and purchased power regulatory asset current | $ 3,759 | $ 6,630

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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481878/980-340-50-1 + Details
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